The present invention relates to a portable terminal such as a portable telephone or PDA.
In recent years, portable telephones are being used as high function terminals for accessing the Internet, mailing, displaying dynamic and static images, managing schedules and the like, in addition to being used as telephones. Keeping pace with providing these high functions in portable telephones has been the colorization of display units of portable telephones, the increase in resolution of display units, and the manufacture of large screen display units.
In order to provide a large screen display unit without sacrificing portability, the structure most commonly employed recently in portable telephones, which are representative of portable terminals, is one in which a display unit housing and an input unit housing are constructed so as to be able to fold open and shut around a hinge portion. In such portable telephone, the display unit housing houses the display unit and the input unit housing houses character input and operating keys such as the ten-keys and function keys.
However, in a folding portable telephone such as the one described above, when the two housings are folded shut (i.e., are in a closed state) the display unit is hidden inside the two folded shut housings. Therefore, when a message, mail or the like is received it is necessary to open the two housings and expose the display unit to the outside.
In order to solve this type of problem in the folding portable telephone, Japanese Patent Application Laid-Open (JP-A) No. 2002-158758, for example, discloses a portable electronic instrument with a rotation mechanism, wherein the display unit is visible to the outside in a closed state. In this closed state the display unit housing, in which the display is provided, is superimposed on the input unit housing, in which character input and operating keys are provided. In addition, JP-A No. 2001-292213, for example, discloses a structure in which, by using an opening and closing radio communication device that has a slide mechanism, the display unit is visible to the outside in a state in which the two housings are superimposed in the same manner as above (i.e., in a closed state).
Here, it should be noted that regardless of whether the structure of the portable terminal includes a slide mechanism, a rotation mechanism, or a folding mechanism, a state in which the display unit housing is superimposed on the input unit housing is referred to below as a “closed state.” In contrast, the state in which the two housings are slightly opened, moderately opened or completely opened from this closed state is referred to below as an “open state”.
It should also be noted that above described portable terminals having displays visible to the outside in the terminal's closed state also allow a user to read mail and confirm received messages, unlike a conventional folding portable telephone. Therefore, it might be concluded that the only reasons for the portable terminal to be placed in an open state would be for inputting characters or for having a telephone conversation.
As can be seen from the above description, the portable terminal may be switched from a closed state to an open state in order to input characters, for example, in an address book or to compose a mail. When the terminal is switched, the character input operation unit such as a ten key gets exposed to the outside. However, in currently available portable terminals, it is often necessary to operate a hierarchical menu subsequently to (or prior to) the portable terminal being placed in an open state so as to set the portable terminal in a character input state (for example by selecting “Compose new” or “Edit”). Consequently, a user has to perform a menu setting operation together with an opening operation.